Air conditioning apparatus



Oct. 26, 1965 R. H. TULL AIR CONDITIONING APPARATUS 3 Sheets-Sheet 1Filed June 20, 1963 Q if Oct. 26, 1965 R. H. TULL 3,213,936

AIR CONDITIONING APPARATUS Filed June 20, 1963 5 Sheets-Sheet 2 INVENTORRobert H. Tull Oct. 26, 1965 R. H. TULL 3,213,936

AIR CONDITIONING APPARATUS Filed June 20, 1963 5 Sheets-Sheet 5 mun.

This invention relates to air conditioning apparatus, and particularlyto means for controlling air flow through such apparatus.

In air conditioning apparatus in which heating is provided as one of thefunctions, a problem exists in providing a gravity rating for thesystem.

The so-called gravity rating is a measure of the heating capacity of theunit due to natural circulation of air over the heating coils when theblower is not operating. This is a feature desired by many who prefer toshut down the blower while the heating means remains functioning, toprovide a quieter operating unit during the night. However, in most airconditioning units the remote location of the air inlet from the heatingunit together with the location of the blower in the duct tend toprevent the natural flow of air over the heater and thereby lessen thegravity rating of the unit.

It is therefore an object of the invention to provide air conditioningapparatus having air flow over the conditioning means when the blower isnot operating.

Another object of the invention is to provide a damper arrangement forproviding air flow over the conditioning means due to gravity flow,which arrangement is operated in response to air flow caused by theblower.

Another object of the invention is to provide a damper arrangement forproviding gravity flow in an air conditioning unit, which arrangement issimple in construction and may be inexpensively manufactured.

These objects, and other objects which will become apparent as thedescription proceeds, are achieved by providing an air conditioning unithaving an inlet for drawing air from the enclosure to be conditioned,and an outlet for discharge of conditioned air to the enclosure. Wallsof the unit housing define a duct etween the air inlet and the airoutlet and disposed in the duct are a blower, heating coils and anyadditional conditioning means which are desired.

The in ention further provides an opening in the duct disposed upstreamof the heating coils, considered in the direction of air flowtherethrough, and in spaced relation below the heating coils. Theopening communicates with the enclosure and is provided with a damperwhich opens into the duct serving to cover the opening when in theclosed position. The damper is so located, and so constructed, that thepressure in the duct caused by the blower forcing air therethrough issufficient to maintain the damper in the closed position. When theblower is shut down, the damper returns to an open position and airflows from the enclosure, through the opening and over the heatingelement due to natural gravity flow.

For a better understanding of the invention reference should be had tothe accompanying drawings, wherein:

FIGURE 1 is a front elevational view of a curtainwall type airconditioner having the invention employed therein;

FIG. 2 is a top plan view of the air conditioning unit shown in FIG. 1having the upper panels removed to better show the arrangement of thecomponents;

FIG. 3 is a longitudinal sectional view taken along line lIlIII of FIG.2;

FIG. 4 is an enlarged fragmentary transverse sectional view taken alongline IV-IV of P16. 2;

ates Patent FIG. 5 is an enlarged fragmentary perspective view showing aportion of the unit in detail; and

FIG. 6 is a fragmentary view similar to FIG. 5, but showing an alternateembodiment of the invention.

Although the principles of the invention are broadly applicable to airconditioning units in general, the invention has been herein illustratedas employed in an air conditioning unit suitable for installation in theoutside wall of a building, and will be so described.

Referring to the drawings, especially FIGS. 1 and 2, there is shown anair conditioning unit 1% installed adjacent a building wall 11 having anopening provided to accommodate the fresh air side of the coolingsystem.

The cooling system contained in the conditioning unit 10 is aconventional compressor-condenser-expander type refrigerating circuit,and only those components deemed necessary for a complete explanation ofthe present invention have been shown in the drawings.

The fresh air side of the unit it contains an electric motor-compressorunit 12, a refrigerant condenser 13, and a mixed flow fan and motorassembly 14. The fan and motor assembly 14 operates in the usual mannerto draw fresh air into the unit 10 and discharge the air over therefrigerant condenser 13, as illustrated by the arrows shown in FIG. 2.

The room air side of the unit 10 contains the refrigerant evaporator 16,finned heating coils 17 which may receive steam or hot water, andcentrifugal blower assembly 18 which operates to draw air from theenclosure and to cause the flow of air over the refrigerant evaporator16 and the heating coils 17 prior to being discharged into theenclosure.

As best shown in FIGS. 3 and 4, air from the en- H closure is drawn intothe unit 18 through the inlet opening 19 and the centrifugal blowerassembly 18 from where it flows into a duct formed by walls of the unit10. The air then passes over the evaporator 16 and flows upwardly pastthe heating coils 17, after which it is discharged through an outletopening 21 which is located adjacent the front of the unit 16 anddirectly above the heating coils.

Referring now to FIGS. 1 and 4, there is shown an opening 22 adjacentthe lower portion of the unit 10 communicating with the enclosure. Theopening 22 is provided with a damper 23 which is pivotally supportedadjacent the lower side of the opening as by a pair of hinge members 24and 26. The damper 23 opens inwardly, and is biased toward the openposition shown in solid lines of FIG. 4, where it is supported by thecover plates 27 and 28 of the evaporator 16.

As best shown in FIG. 5, each of the hinges 24 and 26 have a spring 29disposed between the damper 23 and the unit 14}, tending to lightlyforce the damper away from the opening 22.

In operation, when the unit is calling for heating or cooling, air fromthe enclosure is drawn through the inlet opening 19, into the duct ofthe unit 10 and over the conditioning elements 16 and 17. After beingheated or cooled the air is discharged to the enclosure at the outletopening 21. The spring member 29 is so designed that the pressure causedby air flowing through the duct overcomes the spring pressure and causesthe damper 23 to remain in the closed position as shown in phantom linesin FIG. 4. When the blower is not operating, the drop in pressure causedby insufficient air flow in the duct eliminates the force overcoming thespring pressure, and the damper moves to the open position.

With the damper 23 in the opened position as shown in FIG. 4, air fromthe enclosure will be caused to enter through the opening 22 and flowthrough the duct between the opening and the heating coils 17. The heatof the coils 17 causes the Warm air to rise through the opening 21 andthe air flows through the unit 10, as shown by the arrows in FIG. 4, dueto gravity flow or natural convection.

Although the damper 23 is shown biased toward an open position in theduct by the spring members 29, the damper may be designed in a mannerwhereby the center of gravity of the damper would cause the damper toopen, thus eliminating the use of a spring member.

Referring to FIG. 6 wherein such arrangement is shown, it will be notedthat a damper 23a is disposed in the structure in a manner similar tothe damper 23 of the prior embodiment, but with the springs 29 omitted.

The damper 23a has a pair of inwardly sloping surfaces 31 and 32comprising the greater mass of the damper. By constructing the damper23a as shown, the center of gravity is located inwardly of the duct withrespect to the pivotal axis 33 of the hinges 24 and 26. The resultantunbalance force causes the damper 23a to be biased toward an openposition when the blower 18 is not operating, but is of a magnitudewhich is overcome by pressure caused by air flow in the duct when theblower is operating. The damper 23a thereby functions similar to thedamper 23 of the prior described embodiment, but without use of thesprings 29 to create the biasing force.

In addition to the advantage obtained by having gravity flow caused bythe heating elements 17, it is obvious that a reverse flow could takenplace when the cooling cycle is terminated. That is, cool air flowingfrom the evaporator 16 would flow downwardly in the duct and cause areverse flow, whereby air would enter at the outlet opening 21 and wouldbe discharged through the opening 22 by gravity flow or convection.

An additional feature of the invention is evident in installations wherethe outer casing of the unit is installed in a building together withthe heating coils 17, and the cooling unit and blower 19 are to be addedat some later time. Such an instance often occurs in new buildings whereonly the heating coils are installed to maintain the interior of thebuilding at a warm temperature during construction. By incorporating theinvention as employed in the unit 10, the damper 23 remains open at alltimes when the blower in inoperative, and therefore the flow of air overthe heating units would take place without installation of the blower18.

It should therefore be evident from the foregoing that the inventionprovides air conditioning apparatus which has air flow over theconditioning means when the blower is not operating. Further, theinvention provides air flow by a damper arrangement which is operated inresponse to air flow caused by the blower of the air conditioning unit.The invention therefore provides gravity flow in an air conditioningunit by employing an arrangement which is simple in construction and maybe inexpensively manufactured.

While the invention has been shown in but two forms, it will be obviousto those skilled in the art that it is not so limited, but issusceptible of various additional changes and modifications withoutdeparting from the spirit thereof.

What is claimed is:

1. Air conditioning apparatus comprising:

a housing including a first room air inlet, an air outlet adjacent thetop of said housing, and means defining a passage connecting said firstinlet with said outlet;

blower means selectively operable for forcing air through said passagefrom said inlet to said outlet;

heating means in said passage;

a second room air inlet for said passage, said second inlet beinglocated upstream from said heating means, relative to the direction ofair flow through said passage, and generally below said heating means;and

a damper for said second inlet biased toward an open position to permitgravity convection of air through said second inlet and upwardly pastsaid heating means to said outlet when said blower means is inoperative,and operable to close said second inlet in response to a pressurecondition in said passage arising from operation of said blower means.

2. Apparatus according to claim 1 including:

spring means for biasing said damper toward said open position.

3. Apparatus according to claim 1 wherein:

said damper is pivotally supported along its lower edge and has itscenter of gravity vertically offset from said pivotal support to gravitybias said damper toward said open position.

4. Air conditioning apparatus comprising:

a cabinet including a central portion containing selectively operable,separate, heating and cooling coils, and an end compartment containingblower means;

a first room air inlet in said end compartment for said blower means;

an air outlet adjacent the top of said central portion, said heatingcoil being disposed closely below said outlet;

means defining a passage for air flow forced by said blower means fromsaid first room air inlet to said outlet, said passage including, insequence, said blower, said cooling coil, said heating coil, and saidoutlet;

a second room air inlet in the central portion of said cabinet, saidsecond inlet being disposed generally below said heating coil, and onthe downstream side of said cooling coil;

a damper for said second room air inlet; and

means biasing said damper to an open position in the absence of bloweroperation and yieldable to permit said damper to move to a closedposition in response to the pressure created in said passage byoperation of said blower means.

References Cited by the Examiner UNITED STATES PATENTS 1,876,547 9/32Ashley 53 X 2,191,224 2/40 Adair 165-126 X 2,552,396 5/51 Brandecker62426 X 2,723,616 11/55 Gannon 98-38 2,775,188 12/56 Hubbard 98-382,884,228 4/59 Jor-gensen 62-426 X FOREIGN PATENTS 823,497 12/ 51Germany.

ROBERT A. OLEARY, Primary Examiner. CHARLES SUKALO, Examiner,

1. AIR CONDITIONING APPARATUS COMPRISING: A HOUSING INCLUDING A FIRSTROOM AIR INLET, AN AIR OUTLET ADJACENT THE TOP OF SAID HOUSING, ANDMEANS DEFINING A PASSAGE CONNECTING SAID FIRST INLET WITH SAID OUTLET;BLOWER MEANS SELECTIVELY OPERABLE FOR FORCING AIR THROUGH SAID PASSAGEFROM SAID INLET TO SAID OUTLET; HEATING MEANS IN SAID PASSAGE; A SECONDROOM AIR INLET FOR SAID PASSAGE, SAID SECOND INLET BEING LOCAXTEDUPSTREAM FROM SAID HEATING MEANS, RELATIVE TO THE DIRECTION OF AIR FLOWTHROUGH SAID PASSAGE, AND GENERALLY BELOW SAID HEATING MEANS; AND ADAMPER FOR SAID SECOND INLET BIASED TOWARD AN OPEN POSITION TO PERMITGRAVITY CONVECTION OF AIR THROUGH SAID SECOND INLET AND UPWARDLY PASTSAID HEATING MEANS TO SAID OUTLET WHEN SAID BLOWER MEANS IS INOPERATIVE,AND OPERABLE TO CLOSE SAID SECOND INLET IN RESPONSE TO A PRESSURECONDITION IN SAID PASSAGE ARISING FROM OPERATION OF SAID BLOWER MEANS.